OpenCV ERROR: convert_cascade: error while loading shared libraries: libml.so.2.1: cannot open shared object file: No such file or directory

Question

I'm following http://note.sonots.com/SciSoftware/haartraining.html to train my cascade classifier, it has created some folder in my data folder, I want to create the xml file using convert_cascade executable, but it pops up above error, even though I set environmental variables and created symbolic link in the working directory, but I don't find any libml.so.2.1 in my lib folder. I have seen libopencv_ml.so.2.4 and linopencv_ml.so.2.4.9. even if I create symbolic link to these files, it's still pops above error message. any possible solution. I searched everything. Please help me if anyone knows the answer.